The present invention relates to an injection-molded plastic lid for a container having a first container upper rim part which divergently adjoins the inner wall and which adjoins, via a sharp top rim, an outwardly directed, downwardly sloping second container upper rim part terminating in a downwardly direction apron situated at a distance from the container wall, said plastic lid comprising a first lid inside rim part being capable of engaging said first container upper rim part, which first lid inside rim part merges, via a lid top inside rim into a downwardly sloping second lid inside rim part being capable of engaging with said second container upper rim part, and also a circumferential chamber provided in said second lid inside rim part and sealing means capable of engaging with the second container upper rim part to form a seal.
Such an injection-molded plastic lid for a container for packaging plastic resins, such as polytetrafluoroethylene resin, is disclosed in U.S. Pat. No. 4,674,650. In this known plastic lid, a sealing ring capable of engaging with the second container upper rim part to form a seal has to be fitted in a circumferential chamber provided in the second lid inside rim part.
The fitting of said sealing ring in a circumferential chamber of the lid is, however, laborious and requires considerable time.
Another disadvantage is that, to obtain a reliable seal between the downwardly sloping second lid inside rim part and the second upper rim part of the container, in which there are often irregularities formed during the injection molding, very narrow tolerances have to be met in relation to the dimensions of the sealing ring or of the circumferential chamber provided in a second lid inside rim part.